test: Add chaos tests for number input, decimals, and leading zeros

Co-authored-by: aider (gemini/gemini-2.5-pro) <aider@aider.chat>

calculator/test.js

@@ -457,6 +457,58 @@ test('Backspace', () => {
   checkDisplay('0');
 });
 
+test('Number input chaos: decimals and backspace', () => {
+  // Multiple decimals
+  press('1.2.3');
+  checkDisplay('1.23', 'Second decimal point should be ignored');
+  press('R'); press('R');
+
+  // Multiple leading decimals
+  press('..123');
+  checkDisplay('0.123', 'Multiple leading decimal points should result in 0.123');
+  press('R'); press('R');
+
+  // Backspace over decimal and re-add
+  press('1.23B');
+  checkDisplay('1.2', 'Backspace once');
+  press('B');
+  checkDisplay('1.', 'Backspace twice');
+  press('.');
+  checkDisplay('1.', 'Adding decimal again should have no effect');
+  press('B');
+  checkDisplay('1', 'Backspace a third time');
+  press('.');
+  checkDisplay('1.', 'Should be able to add decimal back');
+  press('45');
+  checkDisplay('1.45', 'Can add numbers after new decimal');
+  press('.');
+  checkDisplay('1.45', 'Another decimal should be ignored');
+});
+
+test('Number input chaos: leading zeros', () => {
+  press('01');
+  checkDisplay('1', 'Leading zero on integer should be replaced');
+  press('R'); press('R');
+
+  press('000123');
+  checkDisplay('123', 'Multiple leading zeros on integer should be replaced');
+  press('R'); press('R');
+
+  press('0.123');
+  checkDisplay('0.123', 'Single zero before decimal is kept');
+  press('R'); press('R');
+
+  press('00.123');
+  checkDisplay('0.123', 'Multiple zeros before decimal are collapsed to one');
+  press('R'); press('R');
+
+  press('123');
+  press('R'); // C
+  checkDisplay(0, 'Clear should result in 0');
+  press('007');
+  checkDisplay('7', 'Can input number with leading zeros after a clear');
+});
+
 test('Repeated equals', () => {
   press('2+3=');
   checkDisplay('5');